Molluscs 131 



refuse to touch them when the animal 

 is known to be alive. 



The Violet Snails, occasionally brought 

 to our shores by the Gulf Stream, are 

 unique in spending their lives floating in 

 mid-ocean. The eggs are arranged upon 

 the underside of a raft of foam-bubbles 

 united by a sticky secretion, a nest re- 

 calling that of certain tropical fresh-water 

 fish. Certain close relations of the violet 

 snails which live ensconced in dainty 

 shells, delicate as bubbles and no larger 

 than a pin's head, take up their abode 

 amongst the spines of starfishes and sea- 

 urchins. 



In the true Whelks, of which the com- 

 mon British species (Buccinum undatum) , 

 which grows to a length of over half a 

 foot, is a familiar example, the siphon 

 pipe may be protruded to a length 

 equalling that of the animal's spiral 

 shell. The shapeless lumps of egg- 

 capsules of the common whelk are known 



